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In a bimolecular reaction, the steric factor P was experimentally found to be 4.5. Which of the following statements are correct?

1. The frequency factor predicted by the Arrhenius equation is greater than the one measured experimentally
2. The activation energy of the reaction remains unchanged by the value of the steric factor
3. Since P = 4.5, the reaction cannot proceed without an effective catalyst
4. The experimentally measured frequency factor is greater than the one predicted by the Arrhenius equation

Correct answer: The experimentally measured frequency factor is greater than the one predicted by the Arrhenius equation

Solution

The steric factor P relates the experimentally determined frequency factor A_exp to the theoretical collision frequency Z: A_exp = P * Z_Arrhenius. When P = 4.5 > 1, the experimental value exceeds the Arrhenius prediction, making option D true. The activation energy Ea is determined by the exponential term and is unaffected by P, making option B also true. Option A contradicts the definition (P > 1 means experimental is higher, not lower). Option C is wrong since P > 1 merely means more collisions are effective than theory predicts.

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